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• inspection (or pedestrian survey) of the ground surface for subsidence features is limited by <br />both topography and vegetation. <br />Geology <br />The coal seams mined in the area are contained with the Mr. Garfield formation of the <br />Upper Cretaceous and Tertiary Ages. The river bottom and flood plain contain sand and gravel <br />deposits of Quaternary age. The Cameo seam in its Upper and Lower benches (respectively <br />the Cameo C and Cameo B Seams) are mined in the Roadside North Portal Mine, while only <br />the Cameo B Seam is mined in the Roadside South Portal Mine. <br />Other seams present within the area are the Palisade and the Carbonera. Both are of <br />limited economic interest. These seams tend to be thin, lenticular and of poor quality. <br />Additional information regarding the geology of the mine permit area can be found in Volume <br />2, Tab 6 of the mine permit application. <br />Mine Production and Design <br />• During 2001, no coal was produced from either the Roadside North or South Portals. <br />The area where mining occurred during 1999 is shown on Figure 1, 2001 Annual Subsidence <br />Survey. The overburden in the areas mined at Roadside North Portal Mine ranges from <br />approximately 1,800 feet to approximately 300 feet. Extraction ratios vary from 43%for a 60 <br />foot by 120 foot entry spacing to 68% where second mining occurs. <br />Projected Mining for 2002 <br />None <br />Surface Inspection <br />Surface inspections (pedestrian surveys) of the mining area are to be conducted in the <br />spring and fall of each year. The 2001 inspections were conducted on April 28, 2001 and <br />October 30, 2001. The areas inspected during the survey are shown on Figure 1, Roadside <br />North Portal, 2001 Annual Subsidence Survey. <br />• <br />2001 Subsidence Report Page 2 <br />